5-Nitronorbornene undergoes a novel rearrangement under acid solvolysis conditions to cis-6-cyclopentena[e]tetrahydro-1, 2-oxazin-3-one (VII). Reduction of VII yields a dihydro derivative, cis-cyclopentana[e]tetrahydro-1, 2-oxazin-3-one (XII), and a tetrahydro derivative, cis-2-hydroxycyclopentaneacetamide (XIII). Hydrolysis of XIII yielded the known lactone, cis-cyclopentana[b]tetrahydrofuran-2-one (XI). Compound VII yielded an unstable nitroso derivative VIII. Compounds VII and XII appear to be the first examples of alicyclic hydroxamic esters and VIII appears to be the first nitroso derivative of a hydroxamic ester. Compound VIII decomposes to an unsaturated lactone, cis-5-cyclopentena[b]tetrahydrofuran-2-one (IX), which undergoes hydrogenolysis to cyclopentaneacetic acid. Probable mechanisms involved in the formation of VII and IX are discussed.